Plant building for an installation and method for operating a plant building

ABSTRACT

The operations building comprises a cleaning chamber and a pump chamber with a pump for cooling water, the pump chamber directly adjoining the cleaning chamber and having such a chamber geometry that, during operation of the plant, disruptive vortices are avoided on account of a high flow speed of the cooling liquid. Arranging the two chambers directly adjacent to one another results in reduced costs on account of the absence of the hitherto conventional calming sections.

[0001] The invention relates to an operations building for a plant, inparticular for a power-generation plant, which has a pump chamber and acleaning chamber for cooling water. The invention also relates to amethod of operating the operations building.

[0002] In an industrial plant, in particular in a power station forgenerating power, cooling water is necessary for operating the plant. Atypical example for the use of cooling water is the cooling of steam ina cooling tower of a power station. In this case, the cooling water isgenerally removed from a natural reservoir, for example from a river orlake, and first of all cleaned in the cleaning chamber in order then tobe sent to plant components via the pump chamber, by a pump arrangedtherein. In large-scale plants, the delivery capacity of the pumpingsystem is a number of cubic meters of cooling water per second. The flowpaths, the cleaning arrangements for cleaning the cooling water, thepump chamber and, in particular, the pump are of correspondinglyvoluminous design. The behavior of the cooling liquid flowing into thepump is decisive for reliable and permanent disruption-free operation ofthe pump. In particular an as far as possible vortex-free flow into thepump is necessary for this purpose.

[0003] In terms of design, the cleaning chamber and the outlet crosssection thereof are usually very narrow and high, whereas the pumpchamber, which is arranged downstream of the cleaning chamber in termsof flow, is wide and flat and designed, for example, as a covered pumpchamber. These extremely different chamber geometries and internals inthe cleaning chamber, or downstream of the same as seen in the flowdirection, cause turbulence in the cooling liquid. In order to preventsaid turbulence or vortices resulting in the formation of surface orbase vortices which are disruptive for the pump, a calming section isusually provided between the cleaning chamber and the pump chamber. Saidcalming section requires a not inconsiderable amount of space, whichadversely affects the costs during the production of the operationsbuilding.

[0004] The book by Lueger “Lexikon der Technik” [Lexicon of technology]4th edition; volume 6; Lexikon der Energietechnik und Kraftmaschinen[Lexicon of power engineering and prime movers], A-K, edited by Rudolfvon Miller, Deutsche Verlags-Anstalt GmbH, Stuttgart, 1965, pages666-667 and pages 669-670, discloses an operations building for apower-generation plant. The operations building has a pump chamber forarranging a pump for cooling water and also a cleaning chamber. Theoperations building is designed as an intake structure on a free body ofwater with a number of intake chambers such that the water flows to theindividual intake chambers uniformly and as far as possible in avortex-free manner, and that the bottom of the body of water is notswirled up or adversely affected by the inflowing water.

[0005] The article entitled “Pumping stations and heavy duty raw waterpumps for the cooling of industrial complexes and power plants” byCourcot, P., Goudy, G. and Lapray, J. F.; GEL Alstom Technical ReviewNo. 12-1993; Paris; ISSN: 1148-2893, discloses a pump arrangement inwhich it is possible to dispense with an otherwise conventional calmingsection between the cleaning chamber and the pump chamber, a rotatingscreening arrangement nevertheless being provided exclusively. In thecase of this prior art, in particular the formation of disruptivevortices in the cooling-water stream is not reliably avoided.

[0006] The object of the invention is to specify an operations buildingfor a plant, and a method of operating an operations building, whichensure reliable plant operation with low plant-production costs.

[0007] The operations-building-related object is achieved according tothe invention by said operations building having a pump chamber forarranging a pump for cooling water and also a cleaning chamber, the pumpchamber directly adjoining the cleaning chamber, it being the case thatthe pump chamber is connected to the cleaning chamber via an intakeopening, which is adjoined by a wall region which runs obliquely inrelation to the chamber side wall, and the flow cross section for thecooling liquid flowing into the pump chamber is tapered by means of apump installed in the pump chamber, with the result that the coolingliquid, in order to avoid disruptive vortices, has a flow speed ofapproximately 2 to 3 m/s.

[0008] The invention takes as its departure point here the surprisingfinding that the cleaning chamber may be arranged immediately in frontof the pump chamber, that is to say that the conventional calmingsections may be dispensed with without disruptive vortices, inparticular surface vortices, occurring in the pump chamber. This isbecause the vortices can be avoided by said expedient geometricalconfiguration of the pump chamber which results in a comparatively highflow speed. This relationship between the flow speed and vorticeformation is surprising since, up until now, it has been assumed thatsuccess is only achieved in precisely the opposite way, that is to saythe lowest possible speed should be set in order to avoid vortices. Thelevel of a sufficient flow speed depends on a number of factors, inparticular also on the quantity of cooling liquid which is to be pumped.In industrial plants with a pumping capacity of a number of cubic metersper second, a flow speed of approximately 0.5 m/s has been provided upuntil now in the calming section. In order to avoid the vortices, ahigher flow speed than this, in particular of approximately between 2-3m/s, is set.

[0009] The decisive advantage of this configuration is that the absenceof the calming section results in the overall volume of the operationsbuilding being reduced and thus in the production costs for theoperations building being reduced to a considerable extent.

[0010] The chamber geometry may be configured such that, duringoperation, the flow speed of the cooling liquid is increased as itpasses into the pump chamber.

[0011] In conventional plants and in the plant described here, the flowspeeds for the cooling water within a cleaning machine arranged in thecleaning chamber are approximately 1 m/s. Whereas, in conventionalplants, this flow speed is reduced to approximately 0.5 m/s through thecalming sections at the inflow to the pump chamber, the presentembodiment, in contrast, provides an increase in the speed in order toform a sufficiently high flow speed.

[0012] An intake opening via which the cooling water flows into the pumpchamber is adjoined by a wall region which runs obliquely in relation tothe chamber side wall. This avoids backflow spaces in the pump chamber,which are a typical cause of the formation of vortices.

[0013] In a particularly preferred embodiment, the pump chamber isdesigned for such positioning of the pump that, by the displacing actionof a pump tube, separation of the flow from the wall is reliablyprevented despite the usually large expansion angle in the inflow regionof the pump chamber.

[0014] With the pump installed, the flow cross section for the coolingliquid flowing into the pump chamber tapers. It is possible here for thediameter of the pump tube to vary over a large range, with the resultthat both pumps with a small tube diameter and high impeller speed andpumps with a large tube diameter and low impeller speed can be insertedinto the same chamber. The tube diameter and the impeller speeds areselected here so as to achieve a low-level so-called “necessary netpositive suction head” (NPSH) for avoiding the so-called cavitation,that is to say the formation and the abrupt bursting of steam bubbles.For this purpose, in particular the distance between the axial center ofthe pump and the chamber rear wall and the distance between the base andthe pump suction bell are designed as a function of the suction-belldiameter and of the size of the chamber.

[0015] In order to avoid wall and base vortices and to achieve anacceptable speed profile in the pump tube, in preferred embodiments thepump chamber has as an alternative, and preferably in combination, thefollowing features:

[0016] a directing sill, running approximately perpendicularly to theinflow direction of the cooling water, on the chamber base in the regionof the pump, said sill serving, in particular, for deflecting the flowin the direction of the pump;

[0017] a longitudinal sill, arranged on the chamber base and runningapproximately in the direction of the inflow direction, as flowresistance for base vortices;

[0018] a continuation of the longitudinal sill on the chamber rear wallas, in particular, a vertically running wall sill;

[0019] a spacing of the wall sill from a chamber ceiling of the pumpchamber, which is designed as a covered pump chamber, in order, foravoiding vortices, to ensure sufficient flow around the pump;

[0020] the chamber side walls, as in the intake region, merge into therear chamber walls via obliquely running wall regions.

[0021] The chamber base is beveled in relation to the chamber rear wall.

[0022] Longitudinal plates, running in particular perpendicularly to thechamber base, are arranged in the intake opening to the pump chamber.

[0023] If required, the interior of the pump chamber is accessible fromthe outside via a flow-connection, which is used for further removal ofcooling water or also for measuring coolant properties. Cooling-waterremoval is provided, for example, for extinguishing purposes or fortemporary cleaning purposes by means of cooling water. To this end,pumps are usually arranged in the pump chamber or in the calmingsection. These act, however, as flow resistance and are often the causeof the formation of surface vortices. With the flow-connection via thechamber wall, there is no longer any need for the arrangement of suchpumps in the interior.

[0024] If use is made of so-called tubular type pumps, in which the pumptube is guided through a chamber ceiling of the pump chamber, it ispossible, additionally or alternatively, for relatively large quantitiesof additional water to be withdrawn above the chamber ceiling. Thiswater leaves the pump chamber through an annular gap between the pumptube and chamber ceiling.

[0025] In addition to the specific provisions made in the pump chamberitself, preferred developments also provide for vortex-avoiding andflow-calming and flow-evening measures, which contribute to evening outthe flow, to be taken in the cleaning chamber. For this purpose, thecleaning chamber, like the pump chamber, has obliquely running sidewalls in the intake region to the pump chamber. Furthermore, a cleaningarrangement is arranged preferably immediately in front of the intakeopening of the pump chamber and fully encloses the same. Said cleaningarrangement preferably has a flow-directing plate on its side which isdirected away from the pump chamber.

[0026] An alternative embodiment is preferably formed by designing thepump as a concrete spiral casing pump, the concrete spiral casingforming the chamber ceiling of the pump chamber. The concrete spiralcasing pump here preferably has a suction tube which projects into thepump chamber.

[0027] In order to achieve the method-related object, the inventionmakes provision, in an operations building having a pump chamber and apump for cooling water arranged therein, and having a cleaning chamberdirectly adjacent to the pump chamber, for the cooling water to becleaned in the cleaning chamber and then to flow into the pump chamberat a flow speed of approximately 2 to 3 m/s, with the result thatdisruptive vortices are avoided.

[0028] The advantages given in respect of the operations building andpreferred embodiments can be transferred analogously to the method.

[0029] Exemplary embodiments of the invention are explained in moredetail hereinbelow with reference to the drawing, in which, in schematicillustrations in each case:

[0030]FIG. 1 shows, in detail form, a lateral illustration in sectionthrough an operations building,

[0031]FIG. 2 likewise shows, in detail form, a lateral illustration insection through an operations building with a concrete spiral casingpump, and

[0032]FIG. 3 shows a plan view of a horizontal section through a pumpchamber.

[0033] According to FIGS. 1 and 2, an operations building 2 for an, inparticular, industrial plant, for example a power station for generatingpower, has a pump chamber 4 and a cleaning chamber 6, which are directlyadjacent to one another via a common chamber wall 8. The cleaningchamber 6 and the pump chamber 4 are in flow-connection with one anothervia an intake opening 10. The pump chamber 4 is designed as a so-calledcovered pump chamber and has a chamber ceiling 28. Arranged in the pumpchamber 4 is a pump 14 which is spaced apart from the chamber base 12and has a pump tube 16. The latter is guided through the chamber ceiling28, an annular gap 29 being formed in the process. In the pump chamber4, a suction bell 17 adjoins the pump tube 16 on the end side. Unlikethe conventional separate pump 14 according to FIG. 1, the pumpaccording to FIG. 2 is designed as a concrete spiral casing pump 14 a.The latter has a concrete spiral casing which is formed by concretecomponents 19 positioned in the building structure or by the buildingstructure itself. From the concrete spiral casing pump 14 a, a suctiontube 20, with suction bell 17 provided on the end side, extends into thepump chamber 4, with the result that the suction bell 17 is at a levelwhich is favorable for operation.

[0034] Arranged in the cleaning chamber 6, immediately in front of theintake opening 10 and covering over the latter completely, is a cleaningarrangement for the cooling water in the form of a filter or of ascreening arrangement 22. It is designed, in particular, as a so-calledbelt screen machine. The latter has a circulating belt screen with aplurality of screen surfaces 24, which serve for cleaning cooling waterin the region of the intake opening 10 and are cleaned in the top regionof the belt screen machine, for example, by jets. The screeningarrangement 22 preferably has further cleaning arrangements (notillustrated specifically) arranged upstream of it.

[0035] The cooling water is usually removed from an natural reservoir,passes, via an inflow opening 26, into the cleaning chamber 6, iscleaned there and is then taken in through the intake opening 10 intothe pump chamber 4 by the pump 14. The operations building 2 isarranged, in relation to the water level of the reservoir, such that,with a natural fluctuation of the water level between a high water levelH and a low water level N, the suction bell 17, that is to say theinflow region of the pump 14, is sufficiently covered over with coolingwater. This is because, if the covering-over level is too low, thequality of the flow in the pump tube 16 is impaired. This applies, inparticular, when the water level drops below the chamber ceiling 28.This situation is thus admissible only for specific operating cases andfor a limited period of time, for example during start-up of the pump14, when the water is fed to the operations building 2 through a longchannel or a long pipeline. A sufficiently high covering-over level, inaddition, helps to avoid the so-called cavitation, that is to say theformation and abrupt bursting of steam bubbles to form a pressure wavewhich adversely affects the material. The illustrated design of the pumpchamber 4 as a covered pump chamber with the chamber ceiling 28counteracts the production of surface vortices.

[0036] The specific provisions made in order to avoid vortices areexplained hereinbelow with reference to FIGS. 1 and 3. As can begathered from FIG. 3, the wall region 30, which adjoins the intakeopening 10, runs obliquely in relation to the chamber side wall 32which, in turn, merges into the chamber rear wall 34 via a rear, obliquewall region 30 a. Arranged on the chamber base 12 is a directing sill 36and a longitudinal sill 38, which have a triangular cross-sectionalsurface and are arranged in relation to one another to form a cross. Inthis case, the longitudinal sill 38 runs in the inflow direction 40 ofthe cooling water. The directing sill 36 serves primarily for deflectingthe cooling liquid into the pump 14. For this purpose, as can begathered from FIG. 1, it is preferably arranged some way in front of thepump axis 42. The directing sill 36 and the longitudinal sill 38 mayhave the same profile or different profiles and/or different dimensions.The longitudinal sill 38 serves for preventing base vortices. It iscontinued in a wall sill 44, which extends vertically upwards on thechamber rear wall 34 but is spaced apart from the chamber ceiling 28 inorder to allow sufficient flow of cooling liquid around the pump 14. Thewall sill 44 serves essentially for easier deflection of the flowingcooling liquid to the pump.

[0037] In the rear region of the pump chamber 4, the chamber base 12 isbeveled in relation to the rear wall regions 30 a and to the chamberrear wall 34 via a corner compensating means 46, which is illustrated bydashed lines in FIG. 1. This serves for improving the deflection of thebase flow and reduces the degree of turbulence of the flow in thisregion. In general terms, the pump chamber 4 is distinguished in that,despite the use of planar boundary surfaces, it does not change the flowabruptly and this, despite the unusually high speed, achieves a lowdegree of turbulence in the pump tube 16. By virtue of the arrangementof bevels in the critical regions, the pump chamber 4 may thus bereferred to as being largely edge-free. The typical flow paths of thecooling liquid are illustrated in the figures by dashed arrow lines. Acorner compensating means in the base region of the intake opening 10 isdispensed with according to FIG. 1 since, there, a stable flow vortex 48forms of its own accord, said flow vortex acting as a so-called“hydraulic ball bearing” in the manner of a stable roller, with theresult that the rest of the flow flows over the flow vortex 48 in anessentially unaffected manner. The flow vortex 48 may be reduced, forexample, by moderate beveling of the base region of the intake opening10.

[0038] In particular the oblique front wall region 30 avoids separationof the flow from the chamber wall. This is achieved not least by thedisplacement action of the pump tube 14, which is decisively determinedby the size and the position of the pump 14 in relation to the wallregions 30. In particular there is a reduction in the flow cross sectionfor the cooling liquid following the intake opening 10, with the resultthat there is an increase in the flow speed. This prevents separation ofthe flow and thus already helps to avoid vortices. On account of thehigh speed of the flow, in addition, the situation where no inparticular stationary flow vortices form on the surface is achieved in astraightforward and reliable manner. This is because such stationaryflow vortices only form stably when there is sufficiently calm flow.Herein resides precisely the essential feature of the chamber geometryby means of which such comparatively calm flow is avoided. With thenormal water level N, the chamber ceiling 28 results in an improvementin the speed distribution in the pump tube 16.

[0039] In order effectively to prevent disruptions from the screeningarrangement 22 in the particularly critical region in the transitionbetween the cleaning chamber 6 and pump chamber 4, in this caselongitudinal plates 50, which are aligned essentially perpendicular tothe chamber base 12, are provided. For a suitable flow guidance, inaddition, the side walls 52 of the cleaning chamber 6 are beveled inrelation to the intake opening 10. Furthermore, at its end which isdirected away from the intake opening 10, the screening arrangement 22has flow-directing plates 54 which are arranged on the borders on thefront side of the screening arrangement 22 in a rectilinear manner or atan oblique angle in relation to said screening arrangement.

[0040] In the chamber wall 8, preferably in the region of the wallregion 30, flow-connections 56 to the interior of the pump chamber 4 areprovided. Cooling water may be removed from the pump chamber 4 via saidconnections without pumps which adversely affect the coolant flow havingto be introduced into the interior of the pump chamber 4. Via theflow-connection 56, it is also possible to take measurements, such as afilling-level measurement, without the flow in the pump chamber 4 beingaffected. Alternatively or additionally, in the exemplary embodimentaccording to FIG. 1, that is to say with the use of a so-called tubulartype pump, it is possible to remove a relatively large quantity ofcooling water. In this case, the cooling water flows through the annulargap 29 between the chamber ceiling 28 and pump tube 16.

[0041] The formation both of base vortices and of surface vortices isreliably avoided by the measures described above. The decisive factorfor this is the high speed in the pump chamber 4. In addition to theessential advantage of dispensing with the calming section, the pumpchamber 4, in addition, can be operated reliably with the pump 14 beingcovered over by cooling water to a comparatively low extent. This isbecause the risk of surface vortices forming is considerably reduced inrelation to conventional configurations. Even if the water level fallsbelow the low water level N to a reduced water level R, which occursunder some circumstances, for example, during start-up and may dropbelow the level of the chamber ceiling 28, the cooling-water flow in thepump chamber 4 is sufficiently stable. The necessary covering-over levelis thus determined essentially just by the cavitation problem. Onaccount of the reduced covering-over level, the necessary overall heightof the operations building 2 is reduced, with the result that theproduction costs can be kept low.

1. An operations building (2) for a plant, in particular for apower-generation plant, having a pump chamber (4) for arranging a pump(14) for cooling water, and having a cleaning chamber (6), the pumpchamber (4) directly adjoining the cleaning chamber (6), characterizedin that the pump chamber (4) is connected to the cleaning chamber (6)via an intake opening (10), which is adjoined by a wall region (30)which runs obliquely in relation to the chamber side wall (32), and inthat the flow cross section for the cooling liquid flowing into the pumpchamber (4) is tapered by means of a pump (14) installed in the pumpchamber (4), with the result that the cooling liquid, in order to avoiddisruptive vortices, has a flow speed of approximately 2 to 3 m/s. 2.The building (2) as claimed in claim 1, characterized in that thechamber base (12) of the pump chamber (4) has a directing sill (36),running approximately perpendicularly to the inflow direction (40) ofthe cooling water, in the region of the pump (14) for deflecting theflow in the direction of the pump (14).
 3. The building (2) as claimedin one of the preceding claims, characterized in that the chamber base(12) of the pump chamber (4) has a longitudinal sill (38), runningapproximately in the direction of the inflow direction (40) of thecooling water, as flow resistance for base vortices.
 4. The building (2)as claimed in claim 3, characterized in that the longitudinal sill (38)is continued on the chamber rear wall (34) as a wall sill (44).
 5. Thebuilding (2) as claimed in claim 4, characterized in that the pumpchamber (4) is designed as a covered pump chamber (4) with a chambercover (28), and in that the wall sill (44) is spaced apart from thechamber cover (28).
 6. The building (2) as claimed in one of thepreceding claims, characterized in that the chamber side walls (32)merge into the chamber rear wall (34) via obliquely running rear wallregions (30 a).
 7. The building (2) as claimed in one of the precedingclaims, characterized in that the chamber base (12) in the rear regionof the pump chamber (4) is beveled in relation to the chamber wall (30a, 32, 34).
 8. The building (2) as claimed in one of the precedingclaims, characterized in that longitudinal plates (50) are arranged inthe intake opening (10) to the pump chamber (4).
 9. The building (2) asclaimed in one of the preceding claims, characterized in that theinterior of the pump chamber (4) is accessible via a flow-connection(56).
 10. The building (2) as claimed in one of the preceding claims,characterized in that the pump chamber (4) has a chamber ceiling (28)through which a pump tube (16) is guided, an annular gap (29) beingformed in the process, with the result that cooling water can bewithdrawn from the pump chamber (4) via the annular gap (29).
 11. Thebuilding (2) as claimed in one of the preceding claims, characterized inthat the cleaning chamber (6) has obliquely running side walls (52) inthe region oriented toward the pump chamber (4).
 12. The building (2) asclaimed in one of the preceding claims, characterized in that, in thecleaning chamber (6), a cleaning arrangement (22) is arrangedimmediately in front of the intake opening (10) to the pump chamber (4).13. The building (2) as claimed in claim 16, characterized in that aflow-directing plate (54) is provided on the cleaning arrangement (22).14. The building (2) as claimed in one of the preceding claims,characterized in that the pump (14) is designed as a concrete spiralcasing pump (14 a), the concrete spiral casing (18) forming the chamberceiling (28) of the pump chamber (4).
 15. The building (2) as claimed inone of the preceding claims, which is designed for a delivery capacityin the order of magnitude of approximately one cubic meter to a numberof cubic meters of cooling water per second.
 16. A method of operatingan operations building (2) for a plant, in particular for apower-generation plant, the operations building (2) having a pumpchamber (4) with a pump (14) for cooling water, and having a cleaningchamber (6) directly adjacent to the pump chamber (4), and the coolingwater being cleaned in the cleaning chamber (6), characterized in thatthe cooling liquid, in order to avoid vortices, flows into the pumpchamber (4) at a flow speed of approximately 2 to 3 m/s.